In the preparation of paper, woven support belts are used for the initial casting, transporting and dewatering of the paper sheet. These belts are known as paper machine clothing. A variety of materials have been used in manufacture of such belts, including metals, and, currently, thermoplastic monofilaments. Thermoplastic materials which have been used in the weaving of these belts include nylon, polyphenylene sulfide (PPS), and poly ether ether ketone (PEEK), as well as polyester monofilaments. The requirements for the monofilaments in the machine and cross machine directions in paper machine clothing often vary. Accordingly, filaments which differ in polymeric composition, size, configuration and filler materials are often used in the machine and cross machine direction. While monofilaments are normally round in cross-sectional configuration, many other shapes have been used in attempts to balance the requirements of strength, durability, abrasion resistance and overall performance in the paper machine clothing.
The present invention provides polymeric monofilaments, particularly useful in paper machine clothing, which exhibit improved wettability and wet abrasion resistance.
Specifically, the instant invention provides an oriented polymeric monofilament having a diameter of about from 4 to 60 mils and having a cross-sectional configuration characterized by 3 to 12 striations on the circumference, each striation having a depth of about from 4 to 20% of the diameter of the monofilament.
The instant invention further provides, in a woven papermaking belt of machine and transverse direction thermoplastic filaments, the improvement wherein at least about 20% of filaments in at least one of the machine and cross machine directions are monofilaments having a diameter of about from 4 to 60 mils and having a cross-sectional configuration characterized by 3 to 12 striations on the circumference, each striation having a depth of about from 4 to 20% of the diameter of the monofilament.